Tabular calculator



Aug. `30 1927.

.INVENTOR fr/wm hf. Hoff/VAN .f I l l l 3 1 o it nl.. w. 0 m, S 9 .Tv le e .n S. 2 R. N0 AT 9 Al M,u FCZ. FME OG H t R D.. .A e WLS ww .A ATn.. F.

Aug. 3o, 1927.

A. W. HOFFMAN TBULAR CMJGULATOR' 2 Sheets-Sheet 2 Filed Sept. 22. 1925 IATTORNEY Patented Aug. 30, 1927.

lPATENT OFFICE.

i Amann W. HoFrMAmor-NEW YORK, N. Y.

TABULAR cALeULAToa.

Application lled' September 22, 17925. Serial No. 51,906. y

The present inventionhas for its principal objects the provisionV of atabular calf culato'r constructed for computation over extremelyy wideranges through the medium of indicator slides arranged in a smallcompact casing; the provision of a calculator of this character havingnovel and improved calculator construction disposed `within a casing;the provision of an improved form of calculator unit adapted to besupported in an inclined position for service; and the provisiongenerally of a `novel and improved y forml of tabular calculator.

Drawings.

Figure 5 is a transverse section on the line 5 5 of Figure 7;

vFigure 6 is a fragmentary sectional view through the casing top and'attached cover therefor taken on the line 6-6 of Figure 1; Figure 7 is aperspective illustration of one of the calculator slides employed;

Figure 8 is aperspective of a computation card for disposition in theslide;

Figure 9 is a perspective view of the transparent cover member for thecomputa- .ton'ard Figure 10v is a fragmentary vertical section through amodified form of calculator Slide. holder; f

'i Figure 11 is a sectional view on the line 11.,11 of Figure 10,:

Figure 12 is a fragmentary section through a slide holder illustratinga; modiled form thereof;

li'gure 13 is a .similar Aview of another modified form of holder;

Figure 14 is a similar View .of still another modified form of holder;

Figure 15 is a similar illustration of `a further modified form ofholder; y y Figure 16 is a top plan view ofthe construction. illustratedin Figure 12 with the slide holder being shown in section.

Description.V

Details of the invention comprise a casing formed of spaced parallelside walls 20 connected by a transversely extending flat bottom 21disposed parallel with an yopen top ofthe casing. The side walls 20 arefurther connected by an inclined rear wall 22 having an out-turnedflange- 23 formed on its upper edgeI and provided intermediate its fends with i u flanges-24 at each side edgethereof.Y The casingis'further provided withfa flat foot section 25 formed on the front edgeof the bottom 21y and disposed at an angle thereto between the'sidewalls ofthe casing.` The outer end of the foot section 25 connects withthe rearwardly inclined front wall 26 of the casing which is rbentbackward upon itselfk at its upper end to form the inwardly rextendingsection 27 having at its lower terminal an upwardly inclinedwshelf 28extending in parallel relation` to the bottom t the open top of thecasing the side walls 2O are provided with out-turned laterallyextending edge flanges 29 extending the longitudinal length Vthereof andadapted for engagement by the inturned edge flanges 30 of a flat coverplate 31 adapted to be slid over the top of the casing from the rear inlocking engagement with the flanges 29. The cover plate 31 is formed ofa metal blank having its rear portion bent upon itself lat a right angleto provide the leg extension 32 having an inwardly inclined terminallange'BB at its end.

Disposed within the casing slightly beneath vthe top thereof is aninclined rack for holding the computing slides of the calculator.l Thisrack is formed of side plates '34 extending adjacent to andparallel withthel side walls 2O of the casing being transversely connected byparallel spaced top and bottom plates 3,5y and 36 respectively. Thefront edge of the rack; is supported upon the shelf 28 formed on thefront wall 26 of laterally extending edge i the casingagbest'illustrated in Figure 3,

a keeper' 38 formed of an angle metal' blank having at opposite ends ofthe inner section thereof upstanding ears 39 in pivotal connection withthe casing walls 2O by means of the eyelets 40. By the pivotalconnection of the keeper with the casing walls, the rear end 37 of.' thecalculator' rack is re tained upon the top of the rear wall of thecasing underneath the inner section of the keeper. The forward end ofthe calculator rack is anchored in position on the shelf 28 by means ofa flanged keeper plate 4l having at opposite endsupstanding ears 42pivoted to the side walls 2O of the casing by means of the eyelets 43,the flange 44 whereof is adapted to engage over the upper edg@ of thefront wall 26 of the casing to dispose the plate 4l at right angles tothe top plate 35 of the rack with its edge engaging the top of the rackretaining saine against accidental withdrawal from within the easing. Itwill be apparent that upon rocking the keeper 38 upon its pivot 40 thatit will swing rearwardly of the casing to clear the rear edge of therack. Likewise the front keeper4l may be rocked upon its pivot todispose the body thereof flatly against the front wall of the casingwhereby the rack may be lifted as a unit from within the easing.

The spaced top and bottom plates and 36 respectively of the calculatorrack are provided with a staggered series of tranfw versely extendingrectangular apertures 45 which receive therethrough the calculatorslides generally indicated at 4G in Figure 4. Each of the calculatorslides, in the preferred form of the invention, comprises asubstantially rectangular metal blank 4'." having its side edgesinturned to provide the spaced flanges 48. The top of each slide isprovided with a tab section 49 teiminating in an upstanding lifting knob50, the tab section below the knob being provided with a struck outshoulder 5l, which shoulder extends oppesitely to a, transversely alinedpair of outstruck shoulders 52 arranged in the body of the slideadjacent the lower end thereof. At the lower end of each slide the bodythereof is provided with a centrally disposed out-struck shoulderextending rearwardly of the slide in the direction of the shoulder 5l,a# d at each side. edge the body of the slide extended to provide thelegs The coinputation card illustrated in Figure 8 is disposed withinthe slide beneath the edge flanges 48 being retained therein by t-hetransparent cover plate 56 also engaged beneath the edge flanges 4S ofthe slide. rlhe bottom edges of the computation card and its cover plateare supported upon the shoulders 52 thus providing aunitary computing`element formed of the slide card and cover plate. As illustrated inFigures 3 and 4,

the normal position of the slides 47 in the calculator r ck is inlowered position with the shoulder 5l of each slide engaging the topplate of the rack leaving only the upper end or tab portions of theslides visible through the open top of the casing.

The normal inoperative position of the casing is shown in Figure l withthe cover in applied position. Then it is desired to employ thecalculator in the working out of some problem, the cover plate $31 isremoved from the casing` and may be inserted beneath the bottom 2l inthe position illustrated in Figure 2 with the leg elevating the rear ofthe casing to impart a forward inclination thereof. Another, and morepermanent service position of the calculator is illustrated in lligures3 and 4 wherein the cover plate after removal is disposed in supportingengagement with the rear wall of the casing, with the edge flanges 24being received under the edge flanges il() of the cover plate. ln thispositionrof the parts the upper edge of the cover plate engages undeiIthe out-turned flange 23 at the top of the rear wall of the casingelevating the casing into a. forwardly inclined position with the frontof the casing resting upon the flat foot section 25, the leg extension232 of the cover plate lying flat to provide in conjunction with thefoot portion 25 a stable support for service position of the calculator.In this position of the parts it will be observed that the rackcontaining the calculator slides is disposed in a forwardly inclinedposition bringing fhe slides into ay substantially upright positionwhereby they may be easily manipulated through the casing` top. lWhenany particular slide desired to be employed its knob is grasped and theslide is drawn upwardly through the rack until the curvd shoulder D atthe lower edge of the sli ie lo engages the bottom plate 3G of the rack.This engagement forces the body 47 of the slide forwardly, and causesthe lower ends 5T of the edge flanges 48 of the slide to engage over theupper face of the bottom plate 36 of the rack whereby the slide will beself supporting in elevated position. In lowering the slide it is merelynecessary to rock the same slightly forward to clear the engagement ofthe flange ends 57 whereupon the slide will drop into its normalposition.

ln the modified form shown in Figure l0 the calculator rack 58 isprovided with a stepped bottom plate 59 arranged in a spaced relationtherefrom approximating the major portion of a slide length. In thismodification of the invention the slides (50 are in all practicalrespects identical with the slides of the preferred form with theexception that the back of each slide is provided with a centrallongitudinal outstruck rib (il which bears against the edge of the rackapertures .45,to provide' for a frictional engagement by a slide s ringtension between the top plate 58 o the rack and the slide at all points.In this form as the slide is elevated, due to the frictional engagementas described it can be disposed in any position as it will automaticallybe retained therein until forcibly retracted within the rack. A

The modification illustratedin Figures 12 and 16 consists in theprovision of a bowed spring 62 arranged within the slot formed in therack plate 63 for engagement against the slide 64, which slideis'provided at its lower end with a stop shoulder 65. In thismodification the bowed spring 62 is secured in posit-ion by means of anattaching flange 66 fastened to the rack plate 63 by means of the.securing elements 67. f Y

In the modication illustrated in` Figure 13 a leaf spring 68 having oneend 69 anchored in a rack plate 70, is extended within the slideaperture for frictional engagement against the' calculator slide 71. Inthe modi- -fied form illustrated in Figure 14the rack plate 72 Visprovided with a strip of rubber or felt 73 arranged in the slidereceiving slots for frictional engagement with the calculator .slide 74.In the modification illustrated in Figure 15 the top plate 75 of therack is provided with spring fingers 7 6 formed by down turning theedges of the plate adjacent the slots through which the calculatorslides 77 are disposed.V In all of the modified forms of the inventionas described, means are provided for frictionally binding the computatorslides against some. portion of the rack for retaining the slides in anyposition in which they may be placed.

As illustrated in Figure 4 the computation cards 55 are-arranged withleft hand unit columns adjacent amount columns wherein theamountadjacent each unit indicates the result of multiplication of theparticular unit by rate number given on the top of the tab which in thisparticular instance is .04%.

Beneath the rate number the indicating number of thepparticular card isdisposed, which in the present instance is 1 indicating that the unitsof the cards run from 1 to 10. It will be apparent that the persondesiring to work out some problem involving the multiplication of someunit or fraction thereof `by some particular unit or fraction of unit,

may find the particular card whose index number shows that the number tobe multiplied is to be found thereon, together with the rate, andelevates the card to extended position in the rack'. By ruiming down thecolumns of figures the desired answer may be found at once and the cardreplaced. It is obvious that the use of this small and compact tabularcalculator enables a great savplate carried thereby, said plate having aseries of spaced slots formed therein, a plurality of metal blanksslidably disposed through said slots, and coact-ing means on said plateand blanks, for retaining said blanks in elevated or retracted positionrelative to said plate.

2. In a calculator, a support, an inclined plate vcarried by saidsupport,'said plate having a series of spaced slots formed therein, aplurality of metal blanks slidably disposed through said slots, andresilient spring fingers carried by said plate and bearin against saidblanks for retaining said blanks in elevated or retracted positionrelative to said plate.

ALFRED W. HOFFMAN.

